After trying various screen protectors, I conclude that this one is probably the best choice. It does not affect the size of the screen like others. It harmoniously follows the original shape of the watch in the side curves, without being excessive or too narrow. I prefer that it is something between a membrane and glass, without being thin at all, it is a very flexible and discreet glass. It sticks easily, quickly, and firmly. If someone needs to remove it to center it better, it is good not to have fully stuck it, but initially, until they find the ideal position, to try it very lightly. It does not make any alteration to the responsiveness and colors of the screen.

I bought the aforementioned protector twice. The first time, it obviously got caught somewhere and came off, causing it to fall. So we thought we hadn't put it on properly.
And on the second purchase, it didn't fit well at all and had gaps. Unfortunately, after just 4-5 days, it completely broke at the corner.